JAN MOIR: Let us pray our Ted’s in the clear 

Superintendent Ted Hastings (Adrian Dunbar) was in a mood this week and no wonder. Ted doesn’t have to look high in the sky to see the sun setting on his career, and the hard day’s long night that awaits.

Thwarted at every turn, boxed in by malignant forces, and distrusted by his superiors, our man with the blouson jacket and trusty biblical exclamations is fast running out of options.

His forced resignation is looming while his beloved AC-12 department is being trimmed and taken over by Patricia Bloody Carmichael (Anna Maxwell Martin).

Arrested: Kate Fleming and Jo Davidson are cuffed in last night’s episode

In addition, despite his oft declared obsession with bent coppers, he seems no closer to unmasking H or revealing the identity of The Fourth Man (or Woman) – who may or may not be the same person or persons.

Indeed, after six entire series, Ted appears no nearer to exposing the network of corrupt police officers involved with organised crime who have thrived on his Central Police pumpkin patch like, well, pigweed.

‘Sometimes you don’t lose, son, you just run out of time,’ he sighed to DI Steve Arnott (Martin Compston) as he left the office after another hard day’s grilling. It was Acting Detective Supt Jo Davidson (Kelly Macdonald) on the hot coals this week, insisting she was not bent, while admitting to a series of actions that were so pure dead bent that it was amazing she could sit up straight.

‘Jesus, Mary, Joseph and the wee donkey!’ cried Ted at one point. This would have been helpful if someone was asking for the names of all key witnesses and livestock present at the Bethlehem Inn about two thousand years ago, but nobody was, so let’s move on.

The interrogation scene lasted nearly 30 minutes – the longest yet in LOD history and taking up half of the entire episode.

Perhaps it was not the best in terms of intensity and suspense – but it was notable for a lovely turn of tearful, ragged regret from Acting Macdonald acting as Acting Supt Davidson; her horror at discovering the real identity of her father was awful to behold.

If she is acting acting acting acting, I will eat my police hat but I fear it is too late for Davidson to gain much audience sympathy; burner phones, planted evidence, wine bar drinks, dead mum, annoying accent? All noted, officer, but it is hard to care about her. Or her story arc.

Can anyone really be coerced so comprehensively for so long? Into a career, a lifestyle, a regrettable tweed suit? We do care about the reptilian Carmichael, though. In a roll call of grotesques who have appeared in LOD over the years, she remains one of the most repellent characters of all, with a deadly line in punctilious malevolence and a lip curl that could put Elvis to shame.

Whether putting Ted in his place or shutting down a useful line of inquiry, Carmichael always smiles with the assurance of a woman who stores venom in her dimples. With such female firepower on display, there wasn’t much for Ted and Steve to do during the cross-examination.

The former only shouted at the Police Federation Rep once, while Steve’s strained expression suggested that inside his silky waistcoat, his back was still giving him gyp. How did we get here? At the beginning of the episode, Davidson and DI Kate Fleming (Vicky McClure) had fled the scene of PC Ryan Pilkington’s (Gregory Piper) killing – but why?

Surely not just because we could then enjoy a barmy ten minutes when they Thelma and Louise-d it in a car chase while being followed by at least a dozen police cars and a helicopter.

When the pair of them barrelled down Market Street, roaring around corners like Steve McQueen in Bullitt, I had to stifle a laugh. At the end, yet another vital witness had been conveniently shot dead by force or forces unknown before he could ever point a finger or utter a word.

PC Ryan Pilkington was shot dead

PC Ryan Pilkington was shot dead

It is certainly true that unwelcome elements of pantomime have surfaced in this series – but what should we expect from a show that has given so much enjoyment and is now heading for the final curtain itself? This is the penultimate episode – and next week’s finale might well be the last Line Of Duty ever.

So many loose ends to tie up! Is Kate in deep undercover? Why won’t Steve answer his emails from Occupational Health? DS Chris Lomax (Perry Fitzpatrick) – what the hell is he all about? Is Carmichael the real Cruella de Vil? And who or what is the missing piece in the H-shaped jigsaw?

That is the thing about Line Of Duty. It always raises more questions than it answers and the biggest one for me is this; why don’t the Organised Crime Group (OCG) just get on with organising crime?

Mother of God, the wasted man hours frittered away on infiltrating the police force when they could have just been getting on with being criminal and doing criminal things. Robbing convoys, workshopping firearms, scaring grannies – whatever the hell it is they do best, why don’t they just get on and do it?

I suppose the answer is that if they did, then they could not get on with the core business of Line Of Duty – tormenting Old Testament Ted. Let us pray that he is not the guilty party. As you were. Until next week.